1. Field of the Invention
The present invention relates to a radio frequency (RF) tag, and particularly relates to an anti-fuse type RF tag using an anti-fuse in a resonance circuit.
2. Related Background Art
Conventionally, an integrated circuit using a silicon-based material has been used in all fields such as a computer, communication and a household electric appliance.
On the other hand, non-contact RF tags and cards using a semiconductor integrated circuit have been widely used in recent years. These tags and cards are equipped with a microprocessor, cryptographic logic and a nonvolatile memory and are suitable for high function, but are expensive for use in such an inexpensive RF tag as to rewrite a few bits, and does not wedge into the market.
In addition, a burglar-proof tag capable of irreversibly recording the only binary signals has been partly in the actual use.
Japanese Patent Application Laid-Open Nos. 2002-245429 and 2002-319004 describe a resonance tag having an LC resonance circuit capable of storing a plurality of bits and writing additional data.
However, although the resonance tag disclosed by Japanese Patent Application Laid-Open No. 2002-245429 and Japanese Patent Application Laid-Open No. 2002-319004 has a function of writing additional data, a capacitor and an anti-fuse are formed through a through hole, so that it has been difficult to secure the thickness uniformity and flatness of an insulating film and to stably-manufacture the resonance tag. The resonance tag also had a problem of having low manufacture efficiency because it needs to prepare the through hole.
The present invention provides an RF tag which is manufactured in a lower cost than a silicon based-integrated circuit, has a memory capacity of a few bits or more and can be stably manufactured, to the field of a non-contact RF tag and card.